<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		/*5、提升层级半层*/
		.box1{
			float:left;
			width: 50px;
			height:50px;
			background-color: red;
		}
		.box2{
			width: 100px;
			height:100px;
			background-color: blue;
		}
	</style>
</head>
<body>
	<div class="box1">
		box1	
	</div>
	<div class="box2">
		box2
	</div>
	
</body>
</html>